METHODS OE MANUFACTURE. . 2'21
Simple subtraction shows that the reduction of 36.33 kilos Fe203 to 32.69'kilos FeO sets free 3.64 kilos of oxygen which unites with the silicon. But 10 kilos of silicon demand 11.43 kilos of oxygen, and therefore 11.43-3.64=7.79 kilos of oxygen must be,supplied by further additions of ore, and since we have already satisfied all the demands of the slag, these further additions must be reduced to the state of metallic iron. These 7.79 kilos of oxygen therefore call for the addition of 25.97 kilos of Fe203, producing 1848 kilos, of metallic iron. . . .
The statement, therefore, is as follows:
1000 kilos pig-iron contain 10 .kilos of silicon. This silicon reqiiires 11.43 kilos of oxygen.
The 11.43 kilos of oxygen are supplied by ferric oxide, part of which is reduced to metallic iron, while the other part is reduced from Fe203 to.FeO, this latter oxide combining with the silica and entering the slag. The amount of'. iron reduced to the metallic state has been shown to be 18.18 kilos, and the amount, of heat absorbecl in dissociating this from" oxygen will be equal to the amount of'heat, formed by its union with oxygen, which will be 18.18X1746= 31,742 calories. The amount of iron present in the.slag; as EeO has been shown-to be 25.43 kilos, and the amount of heat, absorbed in converting this iron from the state of Fe203 to the state of FeO will be the difference between the amount of heat produced by burning this same amount of Fe to the state of FeO and by burning it to Ffi208.. This is as follows: : v ' i.
25.43 X (17461173) =14,571.
The total absorption of heat is as follows:
From Fe reduced to metallic state.................. 81,742
From the reduction of Fe«03 to FeO ....<'....'........ 14,571
Total absorption............................ 46,313
. The total production, of heat will be the amount formed,by the, oxidation of. 10 kilos of silicon plus that created by the union of the resulting silica with oxide of iron, the account standing thus: